An LTE (Long Term Evolution, Long Term Evolution) system supports a time division duplexing (Time Division Duplexing, TDD) mode, where an uplink (UL, Uplink) and a downlink (DL, Downlink) use different timeslots of the same frequency carrier. An LTE TDD system is able to adjust an uplink-downlink configuration (Uplink-Downlink Configuration) semi-statically according to different service types, so as to meet the requirements of services asymmetric in the uplink and the downlink.
In a conventional LTE technology, which uplink-downlink configuration is used is semi-statically configured and therefore, it may occur that the configured uplink-downlink configuration does not match a transient service type, which leads to ineffective utilization of resources. To make the actually used uplink-downlink configuration better match the transient service type and to utilize communications resources more effectively, a dynamic TDD subframe application technology may be used, where some flexible subframes (flexible subframe) are configured in a radio frame. A flexible subframe may be configured dynamically as an uplink subframe or a downlink subframe. FIG. 1 is a schematic diagram of an application of dynamic TDD subframes in a radio frame, where subframes 3, 4, 8, and 9 of each radio frame are flexible subframes.
During the implementation of the present invention, the inventor finds that, in a dynamic TDD subframe application scenario, uplink transmission is performed in a synchronous HARQ (Hybrid Automatic Repeat Request, Hybrid Automatic Repeat Request) mode, and therefore, transmission of a PDCCH (Physical Downlink Control Channel, physical downlink control channel) for scheduling of a PUSCH (Physical Uplink Shared Channel, physical uplink shared channel), transmission of a PUSCH, feedback of an uplink ACK (Acknowledgement, acknowledgement)/NACK (Non-Acknowledgement, non-acknowledgement), and retransmission of a PUSCH are all performed according to a certain timing sequence relationship. This means that there is a timing relationship between uplink and downlink transmission. Therefore, when a flexible subframe is currently configured as an uplink subframe at the current moment and uplink transmission is performed, for example, when transmission over a PUSCH is performed, because of the timing relationship, corresponding uplink transmission, such as feedback of a corresponding uplink ACK/NACK, needs to be performed in the flexible subframe in a subsequent prescribed timeslot. This may cause that the flexible subframe cannot be configured as a downlink subframe within a certain time, which weakens a gain from configuring the flexible subframe and further reduces downlink throughput.